package utils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

/**
 *
 * @author Alberto Ruiz
 */
public final class Encripta {

    private Cipher ecipher;
    private Cipher dcipher;
    // 8-byte Salt
    private byte[] salt = {
        (byte) 0xA9, (byte) 0x9B, (byte) 0xC8, (byte) 0x32,
        (byte) 0x56, (byte) 0x35, (byte) 0xE3, (byte) 0x03
    };
    private int iterationCount = 19;

    public Encripta(String passPhrase) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeySpecException, InvalidKeyException, InvalidAlgorithmParameterException {
        // Create the key
        KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);

        SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
        ecipher = Cipher.getInstance(key.getAlgorithm());
        dcipher = Cipher.getInstance(key.getAlgorithm());

        // Prepare the parameter to the ciphers
        AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);

        // Create the ciphers
        ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
        dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
    }

    public String encrypt(String str) throws UnsupportedEncodingException, IllegalBlockSizeException, BadPaddingException {
        // Encode the string into bytes using utf-8
        byte[] utf8 = str.getBytes("UTF8");
        // Encrypt
        byte[] enc = ecipher.doFinal(utf8);
        // Encode bytes to base64 to get a string
        return new sun.misc.BASE64Encoder().encode(enc);
    }

    public String decrypt(String str) throws IOException, IllegalBlockSizeException, BadPaddingException {
        // Decode base64 to get bytes
        byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
        // Decrypt
        byte[] utf8 = dcipher.doFinal(dec);
        // Decode using utf-8
        return new String(utf8, "UTF8");
    }
}
